1. Field of the Invention
The present invention relates to a camera adapted to take photographs consecutively by taking an identical subject a plurality of times at a predetermined time interval upon one release of a shutter. More particularly, the present invention relates to an improvement of a shutter device for a consecutive taking camera.
2. The Prior Art
Consecutive photograph taking is very convenient in the field of sports and the like, because the position of a subject at various times in a photographic sequence can be recorded as still images.
A consecutive taking camera "Rensha Cardia Byun" (trademark) is marketed by Fuji Photo Film Co., Ltd., the assignee of the present application. In this camera, eight stationary openings are arranged behind respectively associated taking lenses. Eight consecutive scenes are sequentially taken on eight imaging sub-frames, of which four sub-frames constitute an imaging frame of a panoramic size, and all of which constitute a set of two panoramically combined imaging frames. To provide a panoramic frame (36.times. 13 mm), upper and lower portions of a 35 mm full size frame (36.times.24 mm) are masked along the two longer sides. The camera incorporates a shutter device having two rotatable disks. Slits in the disks pass behind eight stationary openings so as to record eight successive images at the different points of the film.
Such a consecutive taking camera has a stopping motor which drives the two disks. At the time of exposure through the disks, the disks are controlled to rotate at high speed. During intervals between the exposures, the disks are controlled to rotate at low speed. It is intended in the camera to record a moving subject in such a form that the motion of the subject is apparently stopped, and to cover a photographic sequence of duration from one to two seconds for recording the eight sub-frames.
In such a consecutive taking camera having a stepping motor, it is possible to predetermine shutter speed and intervals between exposures of the sub-frames as desired. However, there are serious problems of structural complication due to the circuitry of the camera inclusive of the stepping motor, battery, microcomputer and controller. The camera tends to be costly and large.
It is also known in the same field of construct a consecutive taking camera in less costly fashion: a single rotor having an opening is rotated by the bias of a spring, and effects four exposures consecutively. The spring for the rotor is charged during the winding of the film: the film, during winding, derives a sprocket wheel whose rotation charges the spring. When a shutter device is released, the recovery force of the spring causes the rotor to make one rotation.
In the latter known camera, however, high shutter speed and long duration of photographic sequence cannot both be achieved, because a spring having a high recovery force would inevitably shorten the intervals between exposures as well as producing a high shutter speed. A simple spring, in general, has a tendency to progressively decrease in recovery forces as recovery proceeds. Even the single rotation of the rotor considerably changes in speed between the beginning and the end of the rotation, so that there takes place a variation between the sub-frames as to the amount of light received during exposures.
Another problem of the same camera arises when movement of the film charges the spring for the shutter device: the film can be torn at the perforations formed in the film, in course of driving the driven sprocket wheel under the force applied via the film by a film winding mechanism. The film is sometimes not resistant to mechanical engagement of the film with the sprocket.